On May 4, 1970, government forces fired on unarmed civilians, killing four and wounding nine.
That was Kent State. In what was then America.
If you're not old enough to remember, there's a song that will explain it. Have your parents get out their old, creaky Crosby, Stills, Nash & Young records and you can hear it.
If you weren't there, it may seem complicated. In the short version, Nixon (who's in the song) and Kissinger (who isn't) had commissioned some of our spare troops in Vietnam to invade Cambodia. Not everyone approved. As an example, at Kent State, not exactly a font of radicalism, students set fire to an ROTC building.
In response, Ohio Gov. James A. Rhodes sent in the National Guard. Being tough on rowdy students was a sure way to win votes in those days. Getting tough on California's student protesters helped make Gov. Ronald Reagan a national figure.
The Ohio Guard was so tough that it came in with live bullets and turned four live kids into dead ones.
Ten days later, after campuses had exploded, two more students would die at Jackson State in Mississippi.
Try to imagine Americans killing each other this way. You can't.
That's what it was all building up to, though. The colleges had lost control of their students. America had lost control of its young. And so, the grown-ups sent in the troops with live ammo.
In a sense, this would be the last great battle on the home front. The student protesters closed down a hundred or more campuses. Nixon called the students bums. But the bums convinced the politicians who were running the war that they had to find a way out.
At the time, though, that was hardly clear. Many students, and not just the paranoid few, were pretty sure civil war was about to break out. It didn't, of course. Some exams were called off. Some schools didn't hold graduation. At other schools, the graduates came in black armbands.
But, not much later, the war did begin to wind down. And so did the protests. In a few years, the big issue on campus was disco.
The strong feelings on Vietnam never left, though. Vietnam seems to be the war we never get over.
People talk about a divisive nation today. And yet, in an era well before talk radio, a poll that came out a few days after Kent State overwhelmingly blamed the dead students for getting themselves killed. It took until 1990 for Kent State officials to erect a memorial to the dead.
It seems long ago. But Vietnam, never far from the nation's consciousness, is all the rage again. The fall of Saigon is being revisited 20 years later. It is seen as America's shame. There's plenty of shame to go around.
Ask Bob McNamara, the war's chief architect, who wrote a book in which he finally admits he knew the war was wrong long before he left his job as secretary of defense. How many dead rest on his conscience?
And there's this. If the war was wrong, was Bill Clinton (also Phil Gramm and Newt Gingrich and millions of others) wrong for not fighting in it?
Kent State may be a tough anniversary for some. A friend of mine calls it a sacred day of remembrance. The famous picture of that day will be in all the papers again, of 14-year-old runaway (as she was always described) Mary Ann Vecchio crying over the body of a dead student in a country gone mad.
It doesn't seem possible now that any of this happened.
Or maybe it does.
If you're of the far-right-wing-nut persuasion, it must seem very possible. It's a peculiar thing, but at the time of this anniversary we hear the far right, which couldn't be further from the student left, echoing familiar, if distorted, themes.
Twenty-five years later, the far right offers Waco as its Kent State. The far right now claims the FBI for an enemy. In the far-right movement, many want to drop out. In fact, when the new dropouts head to Idaho or wherever, they often run into leftover hippies. These days, it's not the Black Panthers posing with guns. It's the Michigan Militia.
They tell us we're supposed to derive lessons from history, as if we live our lives simply so historians can interpret them. I'm not sure I understand the lesson of the Kent State massacre any more than I do the lesson of Oklahoma City.
But maybe it's simply that America is too willing to declare war on itself. It seems to be a lesson we're still learning.